二化性家蚕滞育发动期间滞育性卵和非滞育性卵的烟酰胺腺嘌呤二核苷酸变化

Change of Nicotinamide Adenine Dinucleotide in Diapause and Non-diapause Eggs of Bivoltine Bombyx mori During Diapause Initiation

为了探究家蚕滞育发动期间呼吸耗氧量下降与烟酰胺腺嘌呤二核苷酸(NAD)含量变化的关系,用高效液相色谱法和分光光度法分别检测在25℃条件下产下后12～72 h的二化性家蚕滞育性卵与非滞育性卵中的还原型NAD(NADH)含量、氧化型NAD(NAD+)含量、乳酸脱氢酶(LDH)活性和胞质苹果酸脱氢酶(cMDH)活性。滞育性卵中的NADH+NAD+含量、NADH/NAD+值及LDH活性分别在产下后18、36、24 h达到峰值,而cMDH活性处于波动中。在产下后24～72 h,非滞育性卵中的NADH/NAD+值极显著低于滞育性卵,而LDH和cMDH活性极显著高于滞育性卵。据此可以推测,滞育发动期间家蚕滞育性卵的NAD+降解增强和NAD+再生下降共同导致呼吸耗氧量下降。

In order to investigate the relationship between reduction of respiratory oxygen consumption and change of nicotinamide adenine dinucleotide （NAD） content during diapause initiation of the silkworm （ Bombyx mori）, reduced NAD （NADH） content, oxidized NAD （NAD ＋） content, lactate dehydrogenase （LDH） activity and cytosolic malate dehydrogenase （cMDH） activity in diapause and non-diapause eggs of a bivoltine silkworm variety from 12 h to 72 h after oviposition at 25℃ were determined by using high performance liquid chromatographic and spectrophotometric methods. NADH ＋ NAD ＋content, NADH/NAD ＋ value and LDH activity in diapause eggs reached the peak value at 18, 36 and 24 h after oviposition respectively, while cMDH activity remained fluctuated. At 24 to 72 h after oviposition, NADH/ NAD ＋ value in non-diapause eggs was extremely significantly lower than that in diapause eggs, while the contents of LDH and cMDH in non-diapause eggs was extremely significantly higher than that in diapause eggs. It is inferred that the enhancement of NAD＋degradation and the decline of NAD ~ regeneration in diapause eggs jointly lead to the reduction of respiratory oxygen consumption during diapause initiation.